<template>
	<view class="imageUploadContainer">
		<view class="imageUploadList">
			<view class="imageItem" v-bind:key="index" v-for="(path, index) in imageListData">
				<image
					:src="path"
					:class="{ dragging: isDragging(index) }"
					draggable="true"
					@tap="previewImage"
					:data-index="index"
					@touchstart="start"
					@touchmove.stop.prevent="move"
					@touchend="stop"
				></image>
				<view v-if="isShowDel" class="imageDel" @tap="deleteImage" :data-index="index">x</view>
			</view>
			<view v-if="isShowAdd" class="imageUpload" @tap="selectImage">+</view>
		</view>
		<image v-if="showMoveImage" class="moveImage" :style="{ left: posMoveImageLeft, top: posMoveImageTop }" :src="moveImagePath"></image>
	</view>
</template>

<script>
export default {
	name: 'robby-image-upload',
	props: ['value', 'enableDel', 'enableAdd', 'enableDrag', 'serverUrl', 'formData', 'header', 'limit', 'fileKeyName', 'showUploadProgress', 'serverUrlDeleteImage'],
	data() {
		return {
			imageBasePos: {
				x0: -1,
				y0: -1,
				w: -1,
				h: -1
			},
			showMoveImage: false,
			moveImagePath: '',
			moveLeft: 0,
			moveTop: 0,
			deltaLeft: 0,
			deltaTop: 0,
			dragIndex: null,
			targetImageIndex: null,
			imageList: [],
			isDestroyed: false
		};
	},
	mounted: function() {
		this.imageList = this.value;

		if (this.showUploadProgress === false) {
			this.showUploadProgress = false;
		} else {
			this.showUploadProgress = true;
		}
	},
	destroyed: function() {
		this.isDestroyed = true;
	},
	computed: {
		imageListData: function() {
			if (this.value) {
				return this.value;
			}
		},
		posMoveImageLeft: function() {
			return this.moveLeft + 'px';
		},
		posMoveImageTop: function() {
			return this.moveTop + 'px';
		},
		isShowDel: function() {
			if (this.enableDel === false) {
				return false;
			} else {
				return true;
			}
		},
		isShowAdd: function() {
			if (this.enableAdd === false) {
				return false;
			}

			if (this.limit && this.imageList.length >= this.limit) {
				return false;
			}

			return true;
		},
		isDragable: function() {
			if (this.enableDrag === false) {
				return false;
			} else {
				return true;
			}
		}
	},
	methods: {
		selectImage: function() {
			var _self = this;
			if (!_self.imageList) {
				_self.imageList = [];
			}

			uni.chooseImage({
				count: _self.limit ? _self.limit - _self.imageList.length : 999,
				success: function(e) {
					var imagePathArr = e.tempFilePaths;

					//如果设置了limit限制，在web上count参数无效，这里做判断控制选择的数量是否合要求
					//在非微信小程序里，虽然可以选多张，但选择的结果会被截掉
					//在app里，会自动做选择数量的限制
					if (_self.limit) {
						var availableImageNumber = _self.limit - _self.imageList.length;
						if (availableImageNumber < imagePathArr.length) {
							uni.showToast({
								title: '图片总数限制为' + _self.limit + '张，当前还可以选' + availableImageNumber + '张',
								icon: 'none',
								mask: false,
								duration: 2000
							});
							return;
						}
					}

					//检查服务器地址是否设置，设置即表示图片要上传到服务器
					if (_self.serverUrl) {
						uni.showToast({
							title: '上传进度：0/' + imagePathArr.length,
							icon: 'none',
							mask: false
						});

						var remoteIndexStart = _self.imageList.length - imagePathArr.length;
						var promiseWorkList = [];
						var keyname = _self.fileKeyName ? _self.fileKeyName : 'upload-images';
						var completeImages = 0;

						for (let i = 0; i < imagePathArr.length; i++) {
							promiseWorkList.push(
								new Promise((resolve, reject) => {
									let remoteUrlIndex = remoteIndexStart + i;
									uni.uploadFile({
										url: _self.serverUrl,
										fileType: 'image',
										header: _self.header,
										formData: _self.formData,
										filePath: imagePathArr[i],
										name: keyname,
										success: function(res) {
											if (res.statusCode === 200) {
												if (_self.isDestroyed) {
													return;
												}

												completeImages++;

												if (_self.showUploadProgress) {
													uni.showToast({
														title: '上传进度：' + completeImages + '/' + imagePathArr.length,
														icon: 'none',
														mask: false,
														duration: 500
													});
												}
												console.log('success to upload image: ' + res.data);
												resolve(JSON.parse(res.data).data.path);
											} else {
												console.log('fail to upload image:' + res.data);
												reject('fail to upload image:' + remoteUrlIndex);
											}
										},
										fail: function(res) {
											console.log('fail to upload image:' + res);
											reject('fail to upload image:' + remoteUrlIndex);
										}
									});
								})
							);
						}
						Promise.all(promiseWorkList).then(result => {
							if (_self.isDestroyed) {
								return;
							}

							for (let i = 0; i < result.length; i++) {
								_self.imageList.push(result[i]);
							}

							_self.$emit('add', {
								currentImages: imagePathArr,
								allImages: _self.imageList
							});
							_self.$emit('input', _self.imageList);
						});
					} else {
						for (let i = 0; i < imagePathArr.length; i++) {
							_self.imageList.push(imagePathArr[i]);
						}

						_self.$emit('add', {
							currentImages: imagePathArr,
							allImages: _self.imageList
						});
						_self.$emit('input', _self.imageList);
					}
				}
			});
		},
		deleteImage: function(e) {
			var imageIndex = e.currentTarget.dataset.index;
			var deletedImagePath = this.imageList[imageIndex];
			this.imageList.splice(imageIndex, 1);

			//检查删除图片的服务器地址是否设置，如果设置则调用API，在服务器端删除该图片
			if (this.serverUrlDeleteImage) {
				uni.request({
					url: this.serverUrlDeleteImage,
					method: 'GET',
					data: {
						imagePath: deletedImagePath
					},
					success: res => {
						console.log(res.data);
					}
				});
			}

			this.$emit('delete', {
				currentImage: deletedImagePath,
				allImages: this.imageList
			});
			this.$emit('input', this.imageList);
		},
		previewImage: function(e) {
			console.log('sds', this.imageList);
			var imageIndex = e.currentTarget.dataset.index;
			uni.previewImage({
				current: this.imageList[imageIndex],
				indicator: 'number',
				loop: 'true',
				urls: this.imageList
			});
		},
		initImageBasePos: function() {
			let paddingRate = 0.024;
			var _self = this;
			//计算图片基准位置
			uni.getSystemInfo({
				success: function(obj) {
					let screenWidth = obj.screenWidth;
					let leftPadding = Math.ceil(paddingRate * screenWidth);
					let imageWidth = Math.ceil((screenWidth - 2 * leftPadding) / 4);

					_self.imageBasePos.x0 = leftPadding;
					_self.imageBasePos.w = imageWidth;
					_self.imageBasePos.h = imageWidth;
				}
			});
		},
		findOverlapImage: function(posX, posY) {
			let rows = Math.floor((posX - this.imageBasePos.x0) / this.imageBasePos.w);
			let cols = Math.floor((posY - this.imageBasePos.y0) / this.imageBasePos.h);
			let indx = cols * 4 + rows;
			return indx;
		},
		isDragging: function(indx) {
			return this.dragIndex === indx;
		},
		start: function(e) {
			console.log(this.isDragable);
			if (!this.isDragable) {
				return;
			}
			this.dragIndex = e.currentTarget.dataset.index;
			this.moveImagePath = this.imageList[this.dragIndex];
			this.showMoveImage = true;

			//计算纵向图片基准位置
			if (this.imageBasePos.y0 === -1) {
				this.initImageBasePos();

				let basePosY = Math.floor(this.dragIndex / 4) * this.imageBasePos.h;
				let currentImageOffsetTop = e.currentTarget.offsetTop;
				this.imageBasePos.y0 = currentImageOffsetTop - basePosY;
			}

			//设置选中图片当前左上角的坐标
			this.moveLeft = e.target.offsetLeft;
			this.moveTop = e.target.offsetTop;
		},
		move: function(e) {
			if (!this.isDragable) {
				return;
			}
			const touch = e.touches[0];
			this.targetImageIndex = this.findOverlapImage(touch.clientX, touch.clientY);

			//初始化deltaLeft/deltaTop
			if (this.deltaLeft === 0) {
				this.deltaLeft = touch.clientX - this.moveLeft;
				this.deltaTop = touch.clientY - this.moveTop;
			}

			//设置移动图片位置
			this.moveLeft = touch.clientX - this.deltaLeft;
			this.moveTop = touch.clientY - this.deltaTop;
		},
		stop: function(e) {
			if (!this.isDragable) {
				return;
			}
			if (this.dragIndex !== null && this.targetImageIndex !== null) {
				if (this.targetImageIndex < 0) {
					this.targetImageIndex = 0;
				}

				if (this.targetImageIndex >= this.imageList.length) {
					this.targetImageIndex = this.imageList.length - 1;
				}
				//交换图片
				if (this.dragIndex !== this.targetImageIndex) {
					this.imageList[this.dragIndex] = this.imageList[this.targetImageIndex];
					this.imageList[this.targetImageIndex] = this.moveImagePath;
				}
			}

			this.dragIndex = null;
			this.targetImageIndex = null;
			this.deltaLeft = 0;
			this.deltaTop = 0;
			this.showMoveImage = false;

			this.$emit('input', this.imageList);
		}
	}
};
</script>

<style>
.imageUploadContainer {
	padding: 10upx 5upx;
	margin: 10upx 5upx;
}

.dragging {
	transform: scale(1.2);
}

.imageUploadList {
	display: flex;
	flex-wrap: wrap;
}

.imageItem,
.imageUpload {
	width: 160upx;
	height: 160upx;
	margin: 10upx;
}

.imageDel {
	position: relative;
	left: 120upx;
	bottom: 165upx;
	background-color: rgba(0, 0, 0, 0.5);
	width: 36upx;
	text-align: center;
	line-height: 35upx;
	border-radius: 17upx;
	color: white;
	font-size: 30upx;
	padding-bottom: 2upx;
}

.imageItem image,
.moveImage {
	width: 160upx;
	height: 160upx;
	border-radius: 8upx;
}

.imageUpload {
	line-height: 130upx;
	text-align: center;
	font-size: 150upx;
	color: #d9d9d9;
	border: 1px solid #d9d9d9;
	border-radius: 8upx;
}

.moveImage {
	position: absolute;
}
</style>
